Mercury battery

Batteries. Many batteries intended for household use contain mercury or mercury compounds. In the form of red mercuric oxide [21908-53-2] mercury is the cathode material in the mercury—cadmium, mercury—indium—bismuth, and mercury—zinc batteries. In all other mercury batteries, the mercury is amalgamated with the zinc [7440-66-6] anode to deter corrosion and inhibit hydrogen build-up that can cause cell mpture and fire. Discarded batteries represent a primary source of mercury for release into the environment. This industry has been under intense pressure to reduce the amounts of mercury in batteries. Although battery sales have increased greatly, the battery industry has aimounced that reduction in mercury content of batteries has been made and further reductions are expected (3). In fact, by 1992, the battery industry had lowered the mercury content of batteries to 0.025 wt % (3). Use of mercury in film pack batteries for instant cameras was reportedly discontinued in 1988 (3). 

C19-0014. The mercury battery, use of which is being discontinued because of the toxicity of mercury, contains HgO and Zn in contact with basic aqueous solution. The redox products are Hg and ZnO. Determine the oxidation and reduction half-reactions and the overall reaction for these batteries. 

C19-0029. Mercury batteries have the following half-cell reactions ... 

Mercury batteries are used widely in everyday life, in applications such as cameras and hearing aids. About 30% of U.S. production of mercury is used in this way, the reason being the constancy of the voltage in the mercury battery, almost to the point of complete discharge. 

A common type of button battery, shown here, contains silver oxide or mercury(ll) oxide. Mercury is cheaper than silver, but discarded mercury batteries release toxic mercury metal into the environment. 

Mercury batteries (cells) consist of a zinc anode and a mercuric oxide cathode. These cells produce a steady 1.3 volts throughout the cells hfetime. 

The small mercury and lithium disposable batteries used for calculators and cameras are variations of the alkaline battery. In the mercury battery, mercuric oxide, HgO, is reduced rather than manganese dioxide. Manufacturers are phasing out these batteries because of the environmental hazard posed by mercury, which is poisonous. In the lithium battery, lithium metal is used as the source of electrons rather than zinc. Not only is lithium able to maintain a higher voltage than zinc, it is about 13 times less dense, which allows for a lighter battery. 

Closely related to the alkaline dry cell is the mercury battery, often used in watches, heart pacemakers, and other devices where a battery of small size is required (Figure 18.10). The anode of the mercury battery is zinc, as in the alkaline dry cell, but the cathode is steel in contact with mercury(II) oxide (HgO) in an alkaline medium of KOH and Zn(OH)2. Zinc is oxidized at the anode, and HgO is reduced at the cathode ... 

FIGURE 18.10 A small Even though mercury batteries can be made very small, they still produce a... 

How many grams of HgO react at the cathode of a mercury battery when 2.00 g of zinc is consumed at the anode ... 

Krishnaswamy R. 1984. Study of availability and composition of metal bearing wastes (generated in titanium extraction and fabrication, aluminum smelters, chromite bearing refractory and foundry sands and mercury battery industries). Report to US Bureau of Mines, Washington, DC, by NH Parker, PE and Associates, La Crescenta, CA. NTIS No. PB84-207091. 

Marie-Davy cell — This was a -+ Bunsen cell with a carbon electrode in a paste of mercury sulfate, i.e., it was a zinc-mercury - battery. 

Ruben cell — This is a zinc-mercuric oxide alkaline cell, more commonly called a mercury -> battery, a type of primary (nonrechargeable) cell, developed by Samuel Ruben during World War II in response to a requirement for batteries with a high capacity-to-volume ratio which would withstand storage under tropical conditions. It was licensed to the RR. Mallory Co., which... 

Mercury batteries with cathodes of a mixture of mercuric oxide and manganese dioxide have a voltage of 1.4 V and a more sloping discharge curve. 

Due mainly to the environmental problems associated with - mercury, the sale of mercury batteries has been banned in many countries during the past years, and they were banned by the International Electrochemical Commission (IEC) and the American National Standards Institute (ANSI). They have been replaced by alkaline-manganese dioxide, zinc/air, silver oxide, and lithium batteries. 

For a time, mercury batteries were quite popular. In the early 1980s, more than 1,000 tons of mercury a year were used to make mercury batteries. These batteries create a special environmental problem, however. People tend to just throw them away when they no longer work. The cases split open easily, releasing mercury into the environment. As a result, much less mercury is now being used to make such batteries. In fact, the use of mercury for making batteries has been discontinued in the United States. 

Q Aithough it iooks different, the mercury battery is much iike the aikaiine battery, except that the mercury battery uses mer-cury(ii) oxide (HgO) in the cathode instead of manganese(iV) oxide (Mn02). 

The mercury battery shown in Figure 21-8c is smaller yet and is used to power devices such as hearing aids and calculators. The mercury battery uses the same anode half-reaction as the alkaline battery, with this cathode halfreaction. 

The mercury battery of the type frequently used in watches, calculators, and hearing aids is a primary cell. Although mercury in the water supply is known to cause health problems, no conclusive evidence has been found that the disposal of household batteries contributes to such problems. Nevertheless, manufacturers are working to decrease the amount of mercury in batteries. In recent years, the amount of mercury in alkaline batteries decreased markedly at the same time, the life of such batteries has increased dramatically. 

The total mercury consumption varied from 270 to 543 kg of mercury annually with a mean value of 393 kg. Moreover, mercury battery consumption of the island underwent a considerable increase from the year 2001 and was at its peak in 2003 with a total contribution of 248 kg of mercury. The general decline in the trend can be associated partly with the govermnent decisions to prohibit use of button cell batteries and mercury usage in paints (except road marking paints) and... 

In the past, mercury batteries were commonly used to power electronic watches and small appliances. The overall reaction for this type of battery is... 

The mercury battery is used extensively in medicine and electronic industries and is more expensive than the common dry cell. Contained in a stainless steel cylinder, the mercury battery consists of a zinc anode (amalgamated with mercury) in contact with a strongly alkaline electrolyte containing zinc oxide and mercury(ll) oxide (Figure 19.8). The cell reactions are... 

Unlike the Leclanche cell and the mercury battery, the lead storage battery is rechargeable. Recharging the battery means reversing the normal electrochemical reaction by applying an external voltage at the cathode and the anode. (This kind of process is called electrolysis, see p. 783.) The reactions that replenish the original materials are... 

Batteries, which consist of one or more electrochemical cells, are used widely as self-contained power sources. Some of the better-known batteries are the dry cell, such as the Leclanche cell, the mercury battery, and the lead storage battery used in automobiles. Fuel cells produce electrical energy from a continuous supply of reactants. 

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